Sometimes the flash size read from bootloader is not correct. This may
forbid SPI Flash driver from reading the the area larger than the size
in bootloader header.
When the new config option is enabled, the latest configured
ESPTOOLPY_FLAHSIZE in the app header will be used to override the value
read from bootloader header.
Allows booting in QIO/QOUT mode or with PSRAM on ESP32-PICO-V3 and
ESP32-PICO-V3-O2 without any config changes.
Custom WP pins (needed for fully custom circuit boards) should still be compatible.
